docs: def _interpretPayload(functioncode, payload):
      r"""Generate a human readable description of a Modbus payload.
      
      Args:
        * functioncode (int): Function code
        * payload (str): The payload that should be interpreted. It should be a byte string.
  
      Returns:
          A descriptive string.
  
      For example, the payload ``'\x10\x01\x00\x01'`` for functioncode 3 should give something like::
      
          TODO: Update
      
  
      """
      raise NotImplementedError()
      output = ''
      output += 'Modbus payload decoder\n'
      output += 'Input payload (length {} characters): {!r} \n'.format(len(payload), payload)
      output += 'Function code: {} (dec).\n'.format(functioncode)
      
      if len(payload) == 4:
          FourbyteMessageFirstHalfValue = _twoByteStringToNum(payload[0:2])
          FourbyteMessageSecondHalfValue = _twoByteStringToNum(payload[2:4])
  
  
      return output